Electrolytic apparatus



E. O. BENJAMIN.

ELECTROLYTIC APPARATUS.

APPLICATION mm we. 1. m1.

1 ,344:,220. Patented J une 22, 1920.

4 SHEETS SHEET I.

E. 0. BENJAMIN.

ELECTROLYTIC APPARATUS.

APPLICATION mm Au ;.1v 1911.

Patented June 22, 1920.

4 SHEETSSHEET Z.

274 ii I/Iiillfl i I I v IIIlIIIllI/IIlIlIlI/Ill arromier E. O. BENJAMIN. ELECTHULYTIQ APPARATUS. mrucnlou FILED Mum; 1911.

1 344,220. Patented June 22, 1920,

4 SHEETS SHEET 3.

E. O. BENJAMIN.

ELECTROLYTIC APPARATUS.

FPLICATYON FILED AUG 1 I917 1,344,220, I I PatentedJune 22,1920.

SHEET SSSSSSS 4.

51 1.3" 55 67 6'7 2 I E|EI- OO i 3'0 &

@Kfi

iii 1M 5 HQ, gig iron MANOR/V5) UNITED STATES PziI'ENT OFFICE.

EDWARD O, BENJAMIN, OF'NEWA RK, NEW JERSEY, ASSIGNOR TO INTERNATIONAL OXYGEN COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

ELECTROLYTIC APPARATUS.

Specification of Letters Patent.

Patented June 22, 1920.

To all whom it may concern:

Be it known that I, Eowano O. BENJAMIN, a citizen of the United States, and resident of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Electrolytic Apparatus, of which the following is a specification.

M y present invention is embodied in an apparatus particularly designed for the purpose of decomposing water for the purpose of producing approximately pure oxygen gas and approximately pure hydrogen gas for various industrial and commercial purposes and although certain features of my invention may be capable of useful employment in other connections or for other or additional purposes, I will describe it in connection with the said purpose for which it was primarily intended.

Apparatus for the above purpose comprises essentially two electrodes and an intervening body of water rendered conductive as for instance by a suitable percentage of acid, salt or base such as soda, potash or similar material. It has been common to employ electrodes of large area and also aseparating member in the electrolyte between the electrodes made of material adapted to resist and, substantially, to prevent mingling of the hydrogen generated on the surface of one electrode with the oxygen generated on the surface of the other electrode or vice versa, while not reventing free electrolytic conduction of t 1e current between the electrodes.

Among the objects of my invention may be mentioned organizing the above mentioned essential elements as a self-contained unit which, though it may be used alone, is adapted to be compactly assembled with and rigidly secured to any desired number of other similar units: to do this in such a way as to insure electr'nl eiliciency and economy and minimum heat radiation as well as economy of floor space and mechanical strength; to have the assembly arrangement so that when necessary or de sired. any cell or cells may be cut out of operation and may be physically removed from intcrnuuliatc positions in the battery,

without any intcrfcrein'e with the mechani-' cal assembly or electrolytic functioning of the other cclls of the battery. To this end, the cll is made thin and self-contained. is

provided with attached glass insulating supports and a ring-bolt above its center of gravity whereby it may be lifted and moved out of assembly.

The cells are preferably similar and each cell consists essentially of a frame which acts as a body, containing all the passageways and regulating devices for maintenance and operation of the cell. The open space within this frame is closed in on each side by the large area metallic plates which serve as the electrodes.

\Vithin the frame and midway between the plate electrodes, is a diaphragm clamped about its entire margin to a flange or ledge on the frame and adapted to serve as a gastight separating medium between the two gases, while permitting free passage of the current therethrough. Other features are making the plate electrodes parallel and close together so that the body of electrolyte between them may be relatively small, saving space, decreasing resistances and making t 1e path of the current in the electrolyte short: arranging electrodes substantially parallel so that the flow of current between the electrodes and its surface density on the electrodes will be substantially uniform; arranging the cell structure, water supply, gas outlets, etc.. so that the gas generating space within the cell will be completely filled with electrolyte except for the gas in formation or transition, and all electrode surfaces exposed within the cell will be useful gas generating surfaces and there will be no non-generating surfaces such as would be liable to waste energy by reversing and acting as a gas battery; the entire area (if the separating medium or asbestos diaphiagm will be entirely below the level of the liquid and will be fully and completely wettcd thereby and so serve elfec tively its function as a gas seal between the oxygen generating compartment and the hydrogen generating compartment; arrang ing for a continiuuis rigid clamp about the entire border of the diaphragm thus render ing it gas-tight at the edges without necessity of using any rubber border or gasket. which. as experience shows, would greatly lessen the life of the diaphragm: assembling the gas collecting arrangements. pressure vents, reservoir, etc.. so that they are closely adjacent and conveniently located: provid ing separating chambers for the respective ill) gases in which the gas will separate out from the electrolyte foam and the alter vapor will he condensed therefrom.

By making (ttt'll cell a separate self-eon tained unit, the eleetrolytie liquid in each Cell is isolated from that in any of the others so that there can he no danger of electrolytic conductivity hetween different cells of the same battery. and no danger of forming secondary eleetrode areas of unlike polarity whereby undesirable quantities of hydrogen may he produred in the region where only oxygen should he and viceversa. etc.

This formation of secondary or localized poles of unlike polarity generating unlike gases in both of the eompartnients where onl v one gas should be. is a dangerous pos sihility even in self-emitained unit rells, hut l avoid it in my present eonstriurtion. as will he explained.

My unitary cell consists of three members which are of metal and home are good eler triral eondini'tors. They are the two electrode plates forming the two main walls of the cell and the intermediate l'ramc roll-- stituting the top. bottom and sides thereof. The elertrodo plates are holted to this frame with intervening non condurting watertight. gas-tight gaskets. \Yith such a row strnction. the frame living of vonducting material and located lictween the elm-trodes and in eleutriral eontal-t with the ronducting electrolyte is in favorable position to short eireuit part of the rurrent. If it did so. the points where the (-urrcnt would naturally enter and leave the frame would he of opposite polarity from the main tlt(' trode in the same compartnu-nt and hero-o would generate the wrong hind of gas in both caimpart'ments.

This I avoid h v taking advantage of the well-known fart that the alert] ical pressure or voltage required to initiate and maintain flow of rurrrnt through one pair of elm-- trodes and the intervening eh'rtrolvte has a rcrtain rritiral value and this voltage. railed the l9FUIll|HlSltl|lll voltage is always the same for any given elertrolvtr. elect rodes and cell. This minimum voltage whirh will foTtL current to flow across one pair of elertrodes must he douhled in order to l'orre rul'rent to flow surressivelv avross two pairs of elevtrodes. llenre a voltage whilrh will foroe current. hetween the main clertrodes of my cell. must he dou'pled hel'ore any rurrent whatever can flow into and out. of the frame sim-e such flow would require the formation f an additional pair of ele trodes and a generation of gas at the four successive transition points. all within a single roll. llenre. I an; free to operate my cell at an) desired voltage between its minimum deromposition voltage and llUlllJlt the decomposition voltage. without danger of auv illi'i'tllt tlovw ing in the frame. For instance. if the critiral minimum voltage for a given cell is 1.5 volts, the safe operating range for that cell will he say 1.6 to 2.9 volts.

An important feature of my invention is arranging for circulation of the electrolyte from the hydrogen side of the asbestos diaphragm to the oxygen side thereof without danger of carrying entrained hydrogen to the oxygen side or vice versa. This is aceomplished by arranging an ollset passage in the bottom of the frame of the cell dea-nding from one extreme edge of the hydrogen side downward, beneath the asbestos partition and emerging at. the extreme opposite edge of the oxygen side of the partition. ireulation through this passage is extremely slow and the gas has abundant time to separate especially when the eireulation is due to a gradual inrrease in the speritir gravity of the lt?(tl't)l \'tt on the one side of the partition. The lighter liquid which is thus displaced upward on the other side is permitted to flow freely hut slowly through passages in the top of the frame, drsrrihed hereinafter, over to the opposite side of the diaphragm. Thi freedom of eirrulatiou of the liquid in response to air equal rhanges in its sperilir gravity increases the rllirienry and uniformity of the gas producing artion of the rurrent and also prolongs the life of the asbestos diaphragm. I believe 1 am the l'u'st to produce a (ell unit in which there is surressfullv maintained a rirrulation of electrolyte between theoxygen and hydrogen sides of the diaphragm without passing through the diaphragm.

By the ahove and other hereinafter desrrihed features of my invention. I am ahle to operate my cell for very long periods of time. prodnring the maximum output of hydrogen and of oxygen with great eronomy of rurrent and hoth gases arc of extreme purity. that is hetter than 99.5% pure.

My invention also inrludes arranging in the frame the gas eolleeting and pressure maintaining instriunentalities int-hiding the e'ollection rhamhers. pressure n'iaintaining w atrr-seals. vents. etu. fol-each of the gases as well as the return passages for overflow of the liquid .from compartment to compartment. and from the water seals. in rolnhination with a supply reservoir for replacing the water vontent of the eleetrolytn as fast as it is used up and turned to gas by the electrofvtir dissociation. This part of the system ineludes intereomnuinicating passages hetween gas eolleeting elaanihersi 'ater sralsfgas vent. stand pipe and the reservoir. from whirh latter the liquid passes into the main hodv of electrolyte in the cell. through a water ealed trap adapted to prevent. reverse passage of the gaseous produvts. The reservoir has two independent outlets into theroll. oneon each side of the dizqihragru.

so that inequality in hydrostatic pressure on the latter is avoided. These two outlets, though closely adjacent are guarded from direct passage of liquid from one side of the diaphragm to the other through the reservoir by arranging an extensive partition between them thereby causing any crossflowing liquid to traverse a very long path so that it will have time to thoroughly free itself from any entrained gas before it passes into the other compartment, where such gas would constitute a dangerous impurity.

These parts are organized so that the danger point of low level of the electrolyte is indicated by bubbling of gases out through the reservoir, wlfile the danger point of pressure is indicated by the bubbling of gases out through the pressure vent. I prefer to use no insulating material of a low melting point, such as parafiin within the cell or any portion of the cell. Also no material readily' decomposed by the electrolyte as glass or porcelain or material adapted to deteriorate before other parts of the apparatus, such as rubber.

Neither of the electrodes contains any of the passageways for the supply of the electrolyte to be dissociated nor for the carrying off of the gas, and neither electrode is sus pended in the electrolyte.

By making the cell thin as well as selfcontained and arranging for complete submcrgcnce of the diaphragm and all electrode surface exposed within the cell, it is rendered particularly adapted for use on shipboard, where, by setting the cell fiatwise to the direction of lateral rolling of the ship, and endwise to the direction of longitudinal pitching. it becomes perfectly usable under all conditions of average or even very rough weather at sea. For this use, as wel as any other use, the cell will stand tilting to an angle of say 35 laterally and say 20 longitudinally without any substantial danger.

The above and other features of my invention will be more fully understood from the following detailed description of a dedesirable embodiment thereof in connection with the accompanying drawings in Which Figures 1. 2, 3 and 9 are respectively side, top and end elevations of the complete cell;

Figs. 4 and 5 are horizontal sections on the lincs AA'and 13-13 of Fig. 1;

Figs. 6 and 7 are vertical transverse sections on the line (-C and D-D, Fig. 1;

Fig. 8 is a central longitudinal vertical section with certain parts shown in side elevation;

Fig. 10 is a horizontal section on the dotted line E-E, Fig. 8 which is broken to different levels in order to show in one view the continuity of the intcrcommunicating passages;

Figs. 11 and 12 are parallel vertical sections through the top of the frame showing the entire construction;

Fig. 13 is a top plan view showing a number of my standard unit cells assembled as u buttery.

The cell as shown in these drawings comprises the rectangular frame 1, which constitutes the top, ends and bottom of the cell. The frame is preferably of cast iron adapted to resist the action of electrolytes such as potash, and is preferably formed as a single integral casting. The large central opening in the frame is boxed in on either side by large metal plates 3, 3, preferably of cast iron, which are applied against the opposite sides of the frame and screwed ti htly down upon an intervening gasket 5 0 any suitable non-conducting material adapted to render the joint air-tight and gas-tight. The bolts 4, 4 screw into the frame 1, which, at the sides, is provided with flanges 6, 6 for this purpose. The inner surfaces of the plates 3, 3 are utilized as the working electrodes and hence the heads and shanks of these bolts must be insulated from the plates 3, 3 by insulating bushings or otherwise so as not to form a metallic conducting path for the current from plate to plate through the frame without passing through the electrolyte within the cell.

Electrode plates are extended at the edge to form electrical terminals 2 of ample area for contact with the terminals of the conductors through which they are to be supplied with current and for distributing said current along the engire edge of the electrodes. The terminal may be securely bolted either to conductors from the source of power or to those of an adjacent cell of the same batterv through holes 2' which are provided for this purpose. Special provisions f?! the latter purpose are described hereina ter.

A flange 7-7 preferably cast integral with the frame, projects inwardly within the opening of the frame in position to support the diaphragm 8 which is secured to it by a rectangular marginal clamp 9 secured by bolts 10 so that the diaphragm is in position to divide the interior of the cell vertically into two parallel compartments. The diaphragm is preferably of heavy, closely woven asbestos fabric, wire gauze, or other porous material adapted to prevent gas bubbles or electrolyte containing them from passing transversely from one compartment into the other without affording any obstacle to the passage of the electric current in the electrolyte. By this means, the hydrogen generated on the inner face of one of the plate electrodes will remain in its compartment or the oxygen generated at the other electrode will remain in its compartment. These gases may be generated on either one in Fig. 10 which is broken to different levels so as to show at a glance the path of the liquid. The precise details of the levels and planes in which these passages extend are accurately shown in the true-plane longitudinal sections of Figs. 11 and 12. Referring for convenience to Figs. 8 and 10, it will be seen that the gas carrying with it more or less moisture, passes up through pipe 30 and bubbles down through the water seal opening .34 into the annular space 42 in the frame casting, the gas escapes through the open top of chamber 35 while any excess liquid flows through the passage 43 into the base of the vent chamber 44; thence through passage 45 into the annular space 46 at the base of the water seal of the other gas collecting chamber 24; thence throu h opening 47 and downwardly under the ba e 48 to the base of the stand pipe 37. From the stand pipe 37 the path is downward through the overflow pipe 38 through passage 49 into reservoir 22.

With the above connections, it will be obvious that both water seals are in hydrostatic connection with the stand pipe 37 and with the gas vent 36; also that excess pressure from either water seal will discharge through the vent 36; pressure from the intermediate water seal discharging backward through passage 45, recess 44 and gas vent 36.

l t is obvious that the last described circulatory system affords a pressure path from one gas producing compartment to the other: but the electrolyte will not equalize through this connection because of the water seal checks which prevent such operation. Any excess pressure which might tend to blow oxygen back or hydrogen forward through passages 43, 45 and the common vent chamber 36 is prevented by the peculiar arrangement of the passages whereby 43 and 45 enter the recess vertically upward on opposite sides thereof and whatever force there may be in such flow, takes effect directly upward and has the eil'ect of driving the gas to the surface of the liquid in the vent cham her 36, whence it will escape to the air in preference to turning downward as it would have to do to enter the passage to the other water seal.

The stand pipe 37 is in position to serve as protection for the glass chambers 36 and for a similar purpose, I have arranged a verlirul rod or metal stud 90 at the opposite end of tho row of said chambers.

(oils of the above described construction may be insulated in any desired way but 1 prefer the insulators which are shown in the drawing as being three in number and arranged in staggered relation. These ati'ord three point support for each cell and they are so located that insulators of adjacent cells will not Contact with each other when assembled in the battery as hereinafter described. Each insulator comprises an insulating shell 51 preferably of glass secured over a stud 52, preferably of iron, by moldable material 53, preferably non-conducting, and the stud 52 is preferably formed integral with an overhanging petticoat 55 of iron which serves as a roof to shed any down-flowing electrolyte out of contact with the sides of the glass insulator. The cast iron is not readily attacked by the potash commonly used in the electrolyte and the pctticoat therefore protects the glass from damage thereby. The stud and petticoat casting is secured to the frame 1, in any desired way, as for instance, by screw stud 54-. These insulating supports raise the bottom of the cell above the floor and afford space for manipulating the arrange- IIlBlltS for drawing off the electrolyte, these latter constituting a very useful feature of my invention. They consist of a passage 60 communicating with the circulating passage 13 and through it with the openings 14, 15. The outlet is closed by a screw plug 61 and there is exterior to the latter an enlarged screw threaded opening for attachment of a pipe elbow or other suitable fitting for drawing oil the electrolyte.

One object in rigidly attaching the insulators to the cell is to make it readily transportable for various purposes, as for instance, to move it into and out of position between other cells and to facilitate such operation I provide a ring bolt 63 in the top of the frame in the line of center of gravity of the cell.

The cells have certain special features of construction whereby they are adapted for assembly in a battery, as indicated in Fig. 13.

By reference to this figure. it will be seen that the cells are placed parallel with each other but out of physical contact, except that the side cdgc extension 2 of the plate electrodes of each cell are rigidly bolted to the corresponding extension 2 of the adjacent electrode plate of the adjacent cell. The spacing out of physical contact and the avoidance of any solid heat insulating'matr rial. between or around adjacent electrodes, decreases liability of forgoing local conducting bridges by spilled or escaped electrolyte, which might operate to concentrate the current path on some one locality of an elec trode and thus overheat the same. The spacing is. however. reduced to the minimum in order to decrease heat losses by having the heated plates closely adjacent and in contact with a relatively small body of intervcning insulating air. The required spacing may be attained where ilat 'elcctrode plates are used. by interposiug a spacing bar th ol' good conducting material, and throughholting the plates into intimate electrical contact therewith by bolts 66. In other cases the plates may he east, with raised lwaring Hltliilttfi as at (3T so that they may he lioited direl'tly together without interposition of ny sparing liar.

The litiliH (ha; hoid the elertrodee to the l'ramea. are arranged llilHylllliltil'l itlly on the top row with I'LHlltt'l {o the hottom row and ii! one of he side rows with reaped to the other side row ao that, as shown in l'ig. 1. none ol the li ii heads in one aide row are on the same le i-l nith h il heads in the Hiilt'! side row. and none oi the liolt heads in the top row are \eriivally in line with the l-olt heal in the hotiom row, liy using the mine pattern l'or hililt'lllif ol lioli heads on the o -po ile iarea il lln' t'til l lit ri'i'llwitiij it. o that in this Htlliilllitl. they are "right! and lvt'im' nnliluaides nt similar H lls may he plarwi in elow relation w ithoiit the possiliility ol' the holi heath oi one i'oiil:l 'lil1 with the iiolta oi the other. even illilllfjlt the -arm he h than the iotai proiertion of the two \rta oi lie-ails.

li i arranging the mten ion 2 io extend alone {he i'liiiii i'dee ol' the i-lw-troilr; l greatly rednre the resistanre and liy hmin; rhea: on ieitii shire ol the plate the resist aliv in ilie' vase ot' i'aat iron is ahont one quarto! what it wonld he with th e-\tenaion ii-i-ii on one 'tiul' only l y [he ahow arrangienienl. the entire path ot' ll-e i-nrreni ihr ogh a hath-r3 is oi the lowest posqhlv 1t=1=illH'(' and hem-e a nnn'h greater a l'rrnia; a it utilized lo perform the ll-Wllll work of uklhiiiiilig' gas.

with In itll-ilt iiiilll the operation ol' the will may in ivpi lllililitlll l1llll'UIJSPIYH' lion. and \illiiliYiL'l iiciiilihi inilii'atril in arr one or more ot tin-n. it may he readily \ll illi'lll' lllii, iinliolied irhni the adja wit well l liooli li'oin an orerliead e'rane in Nl'ilil in the ring h il i and the entire i'vii with attai'hed inmiiatnw and lllltlillltt'tl i'lilll l \'lt' iii li' i and conveyed to a sliitalile lorati n l'or inxi tieation or repair and when repaired. may he I'Plililitil. ail without inti-ri'ering with th opvraiion ol' the re mainin; lillH ot the hatter i.

'lhe end t'illh' may lit vozinerted with the soon-iol' power hy parall l liar strip thrininalas Nth whivh may he of voppe-ip Thom while my inwiition c'clliii'liillliill a lliiHl all-wontainwl veil vapaliln ol' ntirely m-parat and independent operation. many of its novel I'ratniew ariof periiliar adrair lamlot it prel'errwl new a: a quantity liy droe'en and oyrgen pro lni-ing plant wherein a plurality oi" independent thin metalli taniw tilliililllilfl separaiiwin tllli lltllilkfi' i ltiit ol eiwtrolitlmay lie i'tiilltt't'ik'il up in a hatter}. eawh iinil oi whirh I'Hlihifiih of a thin east iron frame, em ir laiing ilia liillilgiil) supported hi hiliannand oppoite ineniaied llai waihwioiing in Eiie i-ai' iy aiihin the frame and heioii the level of the electrolyte therein 50 that their respeelive inner snrt'ares are in contact with the electrolyte on opposite sides of the diaphragm. The exterior portions of the insulated walls are forim-d'with bearing surfaces so that the tanks wan he arranged elose together with the elwirodr walls parallel and the hearing Hui-fares halted together so as to give a low l'U'hlFllllll'l" path for the elertrie enrrent lrorn tank to tank as well as a very strong Illlifllilliiiill i'onstrnrtion. Nevertheless, any tank in the hatter ran he short-rirenited, nnhoited and. with its attaehed insulating alipporta, lifted from the battery by the ring liolt in the frame and removed to a ronvenient plare for inspection or repair and as readily returned to itsplaee in the battery when repairs have heen ronipleted.

The area of the elei-trode snrfare exposed to the rim irulyie within the eel] is predetermined in awordanre with the desired amperage (it riirrent an as to give the desired i'itl'ltlll density. The thi lcness of the cell will he pmli-Lerinined hy the thirkness of elei'lrolyle required between the eieet rode snriares and the diaphragm in order to proterl the latter from disintegration or gas leakage and this in determined by the efl'eetire range whit-h the gases or gas hobbies are [H'Ujliiiti from the surface of electrode hy the elm-tri al foli'es lironght into play by the proreea ol' generaiing: them.

lt will he undersrood that while I speak oi llll insulated walls (onstitilting the working" elm-trodes as living plates; this does not nei-i-ssarily impiy rhat either the exterior or interi r snrlarea are perfertly plain, but only that they are substantially flat; in out line. The inner snri'ares partirnlarly may he rorrneatecl. grooved or otherwise pat term-d or molded Ml as to present a greater tlil i'it't area lo the elei-t'rolyte. and the exteiior airfaremay he and frequently is tornwd or provided with rihs or outstanding hearing snrl'ares whereby they are adapted to labolted to aimiiar surl'aees of a liareni i'elia either with or without the in terpoaed sparing liar.

While l hare t'nlly shown and deserilied all lliidetails of a preferu-d enihodiment of my inventi n. it will he oln'ions that \illiUHS t'iltlifl't'h tillllihitillfi and snliaiitntions ol' the val-ion parts. as well as of arrangement. may in made without deparing i'l'oni tinspirit of my invention.

1 rlaim:

I. An i-lei-trolyiiri ll nnit ronsiatingr of a Hat. wan-alight. nn-tailir tank liarin two at its wails insulated from the land of the tanh an that the inner anrt'ac'ea ol' said insnlated waila may he utilized as ihe working elwtrodea.

:3. An elertrolytie i-ell nii t eonsiaiing ot' a flat. waer-fiezht metallic hmh and means for insulating opposite willie of the tank so that the inner surfaces of said insulated walls may be utilized as the working electrodes, said walls having both side edges extended laterally to form electric terminals, whereby both edges of both electrodes may be bolted to similar terminals 0 a similar cell unit.

3. An electrolytic cell unit, comprising a metallic body portion constituting thg top, bottom and sides of the cell, in combination with metallic plates constituting two other walls of said cell, insulated from said body portion by interposed water -tight, gas tight insulatingmaterial, whereby said insulated walls of the cell may be utilized as the working electrodes thereof.

4-. An electrolytic cell of the class described, comprising a cast iron frame constitutiug the top, bottom and sides of the cell, an asbestos fabric diaphragm rigidly clamped against an inwardly projecting head or flange, extending entirely around the opening within said frame, large area plate electrodes constituting the end walls of said cell and a gas-tight, water-tight. non-conducting medium between said platcs and said frame.

5. An electrolytic cell of the class described, comprising large area conducting plates, an intermediate, relatively thin metallic frame to which said plates are bolted and water-tight, gas-tight insulation interposed between the plates and the frame.

6. An electrolytic cell of the class dcscribed, comprising large area conducting plates, an intervening, relatively thin metallic frame and interposed water-tight, gastight insulation between the plates and the frame, and a diaphragm of non-conductiug but porous structure secured within said frame between said plates. T. An electrolytic cell of the class described, comprising large area conducting plates, an intervening, relatively thin metallic frame and interposed watentight, gastight insulation between the plates and the framc, together with a porous non-conducting diaphragm secured within said frame and. parallel with said plates, said frame being of cast iron and having formed therein the inlets and outlets for supplying the electrolyte to the spaces on both sides of said diaphragm and for separately collecting and removing the gaseous products.

H. :\n electrolytic cell of the class dc scrilr mm ing largr area conducting plates, an lntcrvcniug, relatively thin Hi0 tallic framc and interposed water-tight, gastight insulation between the plates and the frame, togcthcr with a porous mirncomlucting diaphragm secured within said frame and parallel with. said plates, said frame being of cast iron and having molded there in a passage from the bottom of thc ccll on one side of the diaphragm to the bottom of the cell on the other side of the diaphragm.

9. An electrolytic cell of the class describerhconsisting essentially of large area conducting plates, an intervening, relatively thin metallic frame and interposed watertight, gastight insulation between the plates and the frame, together with a porous nonconducting diaphragm secured within said frame and parallel with said plates, said frame being of cast iron and having molded therein a passage from the bottom of the cell on one side of the diaphragm to the bottom of the cell on the other side of the diaphragm. and in the top thereof, a passage from the top of one side of the diaphragm to the top of the other side of the diaphragm.

10. An electrolytic cell of the class described, consisting essentially of large area conductingplates, an intervening, relatively thin metallic frame and interposed watertight, gas-tight insulation between the plates and the frame, together with a porous nonconducting diaphragm secured within said frame and parallel with said plates, said frame being of cast iron and having molded in the top thereof a reservoir having independent passages to the interior of the cell on each side of the diaphragm, a collecting chambcr having an entrance for eler colyte and gas and an exit for escape of elect, olyte, both communicating with the space on one side of the diaphragm, another collecting chamber having an entrance for electrolyte and gas and an exit for electrolyte communicating with the space on the other side of the diaphragm.

11. .An electrolytic cell of the class described, consisting of large area conducting plates and an intermediate porous, nonconducting diaphragm, in combination with means for holding said parts spaced apart and for maintaining a body of electrolyte between and in contact with the inner faces only of said plates.

M. A flat electrolytic cell unit, the flat sides of which consist of large conducting plates and a. body portion which consists of a cast iron frame, in combination with a porous diaphragm within said frame and forming with said plates, two thin parallel compartments adapted to be filled with electrolyte, the thinness of said cell being determined by the minimum distance requircd for protecting the diaphragm from gaseous products formed upon and projected from the inner surface of said plates in the operation of said cell.

13. tlat electrolytic cell unit, the flat side of which consist of large conducting plates and a body portion which consists of a cast iron frame, in combination with a porous diaphragm within said frame and forming with said plates, two thin parallel compartments adapted to be filled with electrolyte, the area of said plates being predetermined in accordance with the amper- HE (Ii H MW ml m

unniz wart umopposite-polarity electrodes, an intervening electrolyte and a orous separating medium in the electroyte between the electrodes, constructed and arranged to divide the space and the body of electrolyte between the electrodes into two single-polarity, opposite-polarity con1- partments and adapted to permit free electrolytic conduction of current therethrough while preventing passage of the gaseous productsof either electrode into the compartment of the other electrode, in combination with passages afl'ording an open path circuit for free circulation of electrolyte from the bottom of one compartment to the bottom of the other compartment, and from the top of the latter compartment to the top 7 of said first mentioned compartment, whereby the electrolyte in sai compartments may equalize their specific gravities as well as their levels independently of any fiow of electrolyte through said separating medium, said passages beingeach formed and arranged with an entrance having a rearwardl and u wardly inclined surface whereby the lig t-weight gaseous products of the reactidn may separate from the flow ing electrolyte and may be guided backward into the compartments whence they came.

20. In an apparatus for electrolytic decomposition of an electrol te constituent, electrodes, an intervening electrolyte and a porous, closely woven asbestos fabric diaphragm in the electrolyte between the electrodes, constructed'an arranged to divide the space and the body of e ectrolyte between the electrodes into two single- )olarity compartments an adapted to permit free electrol ticconduction of current therethrough whi e preventing passage of the gaseousproductsof either electrode into the compartment of the other electrode, -in combination with a passage from the lower part of one compartment to the lower; part of the other compartment around' the diaphragm, whereby the bodies of electrol e in the two compartments may equalize t eir levels without fiow of the electrolyte through said diaphragm.

21. In an apparatus for electrolytic de-- composition of an electrol e constituent, electrodes, an intervening e ectrolyte and a porous closely woven asbestos fabric diaphragm in the electrolyte between-the electrodes, constructed and arranged to divide the space and the body of electrolyte between the electrodes into two single-polaritv, opposite-polarity compartments and adapted to permit free electrolytic conduction of current therethrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with a passage from'thc upper part ofone compartment to the upper part of the other compartment around the diaphragm, whereby the bodies of electrol to in the two compartments may equalize t eir levels without flow of the electrolyte through said diaphragm.

22. In an ai'paratus for electrolytic decomposition 0 an electrolyte constituent, electrodes, an intervening electrolyte and a porous closely woven asbestos fabric diaphragm in the electrol te between the electrodes constructed an arranged to divide the space and the body of electrolyte between the electrodes into two single-polarity, opposite-polarity compartments and adapted to permit free electrolytic conduction of current therethrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with passages affording an open path circuit for free circulation of electrolyte from the bottom of one compartment to the bottom of the other compartment and from the top of the latter compartment to the top of said first mentioned compartment, whereby the electrolyte in said comp ize their specific gravities as well'as their levels independentl of any flow of electrolyte through said diaphragm.

23. In an apparatus for electrolytic decomposition 0 an electrol 'te constituent, electrodes, an intervening e ectrolyte and a porous closely woven asbestos fabric diaphragm in the electrolyte between the electrodes, constructed and arranged,to ,di-=

vide the space and the body of electrolyte between the electrodes into two single-polarity, opposite-polarity compartments and adapted to permit free electrolytic conduction of current therethrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with a passage from the lower part of one compartment to the lower part of the other compartment around the diaphragm, whereby the bodies of electrolyte in the two compartments may equalize their levels without flow of the electrolyte through said diaphragm, said passages being formed and arran ed' with an entrance havin a rearward ly and upwardly inclined surace whereby the light-weight gaseous product of the reaction may separate from the flowing electrolyte and may be guided backward into the compartment whence it came.

24. In an a paratus for electrolytic decomposition 0? an electrol te constituent, electrodes, an intervening e ectrolyte and a porous closely woven asbestos fabric diaphragm in the electrol te between the electrodes, constructed an arran ed to divide the space and the body of e ectrolyte between the'electrodes into two single-polarity, opposite-polarity compartments and artments may equaladapted to permit free electrolytic conduction of current therethrough while preventing passa e ot' the gaseous products of either electrode into the compartment of the other electrode, in combination with a passage from the upper part of one compartment to the upper part of the other compartment around the diaphragm, whereby the bodies of electrolyte in the two compartments may equalize their levels without flow of the electrolyte through said diaphragm, said passages being formed and arranged with entrances each having a rearwardly and upwardly inclined surface whereby the lightweight gaseous products of the reaction may separate from the flowing electrolyte and may be guided backward into the compartments whence they came.

25. In an apparatus for electrolytic decomposition of an electrolyte constituent, electrodes, an intervening electrolyte and a porous closely woven asbestos fabric diaphragm in the electrolyte between the electrodes, constructed and arranged to divide the space and the body of electrolyte between the electrodes into two singlepolarity, opposite-polarity compartments and adapted to permit free electrolytic conduction of current therethrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode. in combination with passages at fording an open path circuit For free circulation of electrolyte from the bottom of one compartment to the bottom of the othcr compartment and from the top of the lattcr compartment to the top of said first mentioned compartment, whereby the electrolyte in said compartments may equalize their specific gravities as well as their levels iudependently of any flow of electrolyte through said closely woven asbestos fabric diaphragm, said passages being each formed and arranged with an entrance having a rearwardly and upwardly inclined surface whereby the light-weight gaseous product of the reaction may separate from the flowing electrolyte and may be guided backwa rd into the compartment whence it camc.

:36. In amapparatus for composition of an electrolyte constituentelectrodes. an intervening clcctrolytc and a porous separating medium in the {?lf.(llill \'t9 between the electrodes. constructed and arranged to divide the space and the body of electrolyte between the electrodes into two singlc-polaritv. oppositepolarity compartments and adapted to permit free elcctrolytic conduction of current thcrethrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with a passage from the lower part of one compartment to the lower part of the other compartment around the separating clcctrolvtic do i medium, whereby the bodies of electrolyte in the two compartments may equalize their levels without How of the electrolyte through said separating medium, together with means whereby the level of the electrolyte is continuously maintained above the topmost portion of said separating medium and above the topmost portion of all electrode surfaces exposed within said compartment.

27. In an apparatus for electrolytic decomposition of an electrolyte constituent, electrodes, an intervening electrolyte and a porous separating medium in the, electrolyte between the electrodes, constructed and arranged to divide the space and the body of electrolyte between the electrodes into two single-polarity, opposite-polarity compartments and adapted to permit free electrolytic conduction of current thercthrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with a passage from the upper part of one compartment to the upper part of the other compartment around the separating medium, whereby the bodies of electrolyte in the two compartments may equalize their levels without flow of the electrolyte thl'ough said. separating medium, together with means whereby the level of the electrolyte is continuously nuiintained above the topmost portion of said separating medium and above the topmost portion of all electrode surfaces cxposed within said compartment.

38. in an apparatus for electrolytic decomposition of an. electrolyte constituent, electrodes, an intervening electrolyte and a porous separating medium in the electrolyte between the electrodes, constructed and arrangcd to divide the space and the body of electrolyte betwccn the electrodes into two single-polarit v, oppositopolarity coinpart ments and adapted to permit tree electrolytic conduction of current therethrough while preventing passage of the gaseous products of either electrode into the compartnu-nt oi the other electrode, in combination with passages affording an open path circuit for free circulation of electrolyte from the bottom of one compartment to the bottom, of the other compartment, and from the top of the latter compartment to the top of said first mentioned compartment, whereby the electrolyte in said compartments may equalize their specific gravities as 'well as thei levels independently of any flow of electrolyte through said separating medium, together with means whereby the level of the electrolyte is continuously maintained above the topmost portion of said separating medium and above the topmost portion of all electrode surfaces exposed within said com partment 29. in an ap iiaratus for electrolytic decomposition of an clectrolvtc constituent,

electrodes, an intervening electrolyte and a porous separating medium in the electrolyte between the electrodes, constructed and ar ranged to divide the space and the body of electrolyte between the electrodes into two single-polarity, o niosite-polarity compart ments and adapted to permit free electrolytic conduction of current therethrongh while preventing passage of the gaseous products of either electrode into the compartment,- of the other electrode, in combina tion with a passage from the lower part. of one comliiartment to the lower part of the other compartment around the separating medium whereby the bodies of electrolyte entrance having a rearwardly and upwardly inclined surface whereby the light-weight gaseous products of the reaction may sepa rate from the flowing electrolyte and may be guided backward into the compartment whence it came, together with means whereby the level of the electrolyte is continuously maintained above the topmost portion.

of said separating medium and above the topmost portion of all electrode surfaces within said compartment.

30. In an apparatusfor electrolytic decomposition of an electrolyte constituent, electrodes, an intervening electrolyte and a porous separating medium in the electrolyte between the electrodes, constructed and arranged to divide the space and the body of electrolyte between the electrodes into two single-polarit opposite-polarity compart ments and a apted to permit free electrolytic conduction of current therethrough iwhile preventing passage of the gaseous products of, either electrode into the compartment of the. other electrode, in combination with a. passage from the upper part oi one compartment to the upper part oi the other compartment around the separating medium, whereby the bodies of electrolyte in the two com artments may equalize their levels without fiir v of the electrolyte through said scparatingnnedium, said passages being forn'ied and arranged with an entrance haw ing a. rearwardly and upwardly inclined surface whereby the light-weight gaseous products of the reaction may separate from 235 the flowing electrolyte and may be guided backward into the compartment whence it came, together with means whereby the level of the electrolyte is continuously maintained above the topmost portion of said separate medium and above the topmost portion ll electrode surfaces exposed within said compartment.

31. In an apparatus for electrolytic decomposition of an electrol tc constituent,

electrodes. an intervening e ectrolyte and a porous separating medium in the electrolyte between the electrodes, constructed and arranged to divide the space and the body oi? electrolyte between the electrodes into two single-polarity, opposite-polarity compartments and adapted to permit free electio lytic conduction of current therethrough while preventing passage of the gaseous products of either electrode into the com partmcnt of the other electrode, in con1bination with passages affording an open path circuit for tree circulation of electrolyte from the bottom of one compartment to the bottom of the other compartment and from the top of the latter compartment to the top of said tirst mentioned compartment, whereby the electrolyte in said compartments may equalize their specific gravities as well as their levels independently of any flow of electrol to through said sepw rating medium, sai passages being each formed and arranged with an entrance haw ing a rearwardly and upwardly inclined surface whereby the light-weight gaseous products of the reaction may separate from the ilowing electrolyte and may be guided backward into the compartment whence it came, together with means whereby the level of the electrolyte is continuously maintained above the top-most portion of said separating medium and above the topmost portion of all electrode surfaces exposed within said compartment.

32. .in an apparatus for electrolytic decomposition of an electrolyte constituent, electrodes. an intervening electrolyte and a porous, closely woven asbestos fabric diaphragm in the electrolyte between the electrodes. constructed and aranged to divide the space and the body of electrolyte be- -t ween the electrodes into two singlepolarity. op )ositc-polarity compartments and adapted to permit free electrolytic conduction of current therethrough while preventing passage oi the gaseous products of either electrode into the compartment of the other electroi'le, in combination with a passage from the lower part of one compartment to the lower part of the other compartment around the diaphragm, whereby the bodies of electrolyte in the two compartments may equalize their levels without flow of the electrolyte through said diaphragm, together with means whereby the level of the elect rolyie is continuously maintained above the topmost portion of said diaphragm and above the topmost portion of all electrode surl'aci's exposed within said compartment.

3?). in an apparatus for electrolytic decomposition oi an electrolyte constituent. eha'tr iies, an intervening electrolyte and a porous closely woven asbestos fabric diatween the electrr'adcs into two single-polarity, UPIiSltt pfllllllty com mrtments and adapted to permit tree electrolytic conduction of current therethr ugh while preventing pas sage of the gaseous products of either electrode into the compartment of the other (lci'trolhn in combination with a passage from the upper part of one compartment to the upper part (It tho other compartn'ient around the diaphragm, whereby the bodies of electrolyte in the two compartments may equalize their levels without How of the electrolyte through said diaph'agm, together with means whercbv the level of the electrolyte is continuously maintained above the topmost portion of said diaphragm and above the topmost portion of all electrode surfaces exposed within said compartment.

347 In an apparatus for electrolytic decomposition oi an electrolyte constituent, electrodes, an intervening electrolyte and a porous closely woven asbestos fabric diaphragm in the electrolyte between the electrodes. constructed and arranged to divide the space and the body of electrolyte lg tween the electrodes into two siugle polari opposite-polarity compartments and adapted to permit free electrolytic conduction of current thcrethrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with passages ailording an open path circuit for free circnlation of electrolyte from the bottom of one compartment to the bottom of the other compartment. and from the top of the latter compartment to the top of said first IllLllllUllGtl compartment, whereby the electrolyte in said compartments may equalize their specific gravities as well as their levels independently of any flow of electrolyte through said diaphragm, together with means whereby the level of the.elcctrolyte is continuously maintained above the top-- most portion of Tsaid diaphragm and above the topmost portion of all electrode surfaces exposed within said cmnpartment.

33. In an apparatus for electrolytic decomposition of an electrolyte constituent, electrodes an intervening electrolyte and a porous closely woven asbestos fabric diaphragm in the tltttlfll "t9 between the electrodes constructed and arranged to divide the space and the body of electrolyte between the electrodes into two single-polarity opposite-polarity compartments and adapted to permit treeelectrolyticconduction of current thcrctlu'tmgh while preventing passagnolthe gaseous products of. citherclectrodc into the mnupartnient oi the other electrode. in combination wil ll a passage from the lower part of one compartment to the lower part of the other compartment around the closely woven a bestos fabric diaphragm. whereby the bodies of electrolyte in the two compartments may equalize their levels without flow of the electrolyte through said diaphragm, said passages being formed and arranged with an entrance having a rear wardlv and upwardly inclined surface whereby the lighbweight gaseous products of the reaction may separate from the Howing electrolyte and may be guided backward into the compartment whence it came, togethcr with means whereby the level of the electrolyte is continuously maintained above the topmost portion of said diaphragm and above the topmost portion of all electrode surfaces exposed Within said compartment.

36. In an apparatus for electrolytic decomposition of an electrolyte constituent, electrodes, an intervening electrolyte and a porous closely woven asbestos fabric diaphragm in the electrolyte between the clec1 trodes, constructed and arranged to divide the space and. the body of electrolyte between the electrodes into two singlepolarity, opposite-polarity compartments and adapted to permit free electrolytic conduction of current therethrough while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with a passage from the upper part of one compartment to the upper part of the other compartment around the closely woven asbestos fabric diaphragm, whereby the bodies of electrolyte in the two compartments may equalize their levels without flow of the electrolyte through said diaphragm said passages being formed and arranged with an entrance having a rearwardly and upwardly incline surface whereby the lightweight gaseous products of the reaction may separate from the flowing electrolyte and may be guided backward into the compartment whence it came, together with means whereby the level of the electrolyte is continuously maintained above the topmost portion of said diaphragm and above the topmost portion of all electrode surfaces exposed within said compartment.

37. In an apparatus for electrolytic decomposition of an electrolyte constituent. electrodes, and intervening electrolyte and a porous closely woven asbestos fabric diaphragm in the electrolyte between the electrodes, constructed and arranged to divide the space and the body of electrolyte between the electrodes into two single polarity, opposite polarity compartments and adapted to permit free electrolytic conduction of current therethro ugh while preventing passage of the gaseous products of either electrode into the compartment of the other electrode, in combination with pas sages affording an open path circuit for free circulation of electrolyte from the bottom of one compartment to thc bottom of the, other com mrtmcnt and from the topmf the openin within said latter compartment to the top of said first mentioned compartment, whereby the electrolyte in said compartments may equalize their specific gravities as well as their levels independently of any flow of electrolyte through said diaphragm, said passages being each formed and arranged with an entrance havinfg a rearwar'dly and upwardly inclined sur ace whereby the lightweight gaseous products of the reaction may separate from theflowing electrolyte and may be guided backward into the compartment whence it came, together with means whereby the level of the electrolyte is continu ously maintained above the topmost portion of said dia hragm and above the topmost portion 0 all electrode surfaces exposed within said compartment.

38. An electrolytic apparatus consisting of a flat metallic cell comprising a body lportion and walls insulated therefrom and aving their inner surfaces arranged as the working electrodes, the top of said body portion being formed with an interior space whereb the level of the electrolyte may be maintalned abovethe topmost portion of said electrode surfaces.

39. An electrolytic cell of the class described, comprisin a cast iron frame constituting the top, ottom and sides of the cell and having an inwardly projecting bead or flange extendin entirely around the tame, a continuous i rigid c amp'coextensive with said head or 1 g. n range "clamped between sai an asbestos fabric diaphragm arwith its ed e portions rigidly flange and clamp,

large area electrodes constituting two of the walls of said cell below the level of the electrolyte therein, and a gas-tight, water tight, non-conducting medium between said plates and said frame.

40. An electrolytic cell of the class described, comprising large area conducting plates, an intermediate relatively thin metallic frame to which said plates are bolted, and water-tight gas-tight insulation interposed between the plates and the frame, the exposed inner surfaces of said lates bein arranged below the level of the liquid in t e cell cavity. .411. An electrolytic cell of the class describ d, comprising large area conducting Iates, an; intervemng, relatively thin metalliciffreme iaiid interposed water-tight, gas- 1t ofijbetween the plates and the frame diaphragm ofnon-conducting material. but porous structure secured within'said frame between. said plates and below the level of the electrolyte in said cell. v

42. An electrolytic cell of the class described, comprising large area conducting lates, an interven ng, re atively thin metalic frame and interposed watertight, gas

and outlets for supplying. the electrolyte to the spaces on both sides of said diaphragm and for separately collecting and removing the gaseous products.

43. An electrolytic cell having opposite walls insulated from the body portion thereof and adapted to serve as electrodes, and a porous, gas-tight diaphragm supported by said body portion so as to divide the space and the body of electrolyte be tween the electrodes into two single-polarity, opposite-polarity gas compartments; said body portion having a reservoir with independent water-sealed connections to each of the compartments, independent separating chambers with water-sealed exits for each of said compartments, a gas vent connected below the level of the electrolyte in both said exit water seals, and an overflow stand pipe connected with said reservoir and with said exit water seals.

44. An electrolytic cell having opposite walls insulated from the body portion thereof and adapted to serve as electrodes, and a porous, gas-tight diaphragm supported by said body portion so as to divide the space and the body of electrolyte between the electrodes into two sing1epolarity, opposite-polarity gas compartments; said body portion having a reservoir with independent water-sealed connections to each of the compartments, independent separating chambers with electrol e entrances and exists and with water-sea ed exits for each of said compartments.

45. An electrolytic cell having opposite walls insulated from the body portion thereof and adapted to serve as electrodes, and a porous, gastight, diaphragm supported by said body portion so as to divide the space and the body of electrolyte between the electrodes into two single-polarity, opposite-polarity gas compartments; said-body portion having a reservoir with independent water-sealed connections to each of the compartments, independent separating chambers with water-sealed exits for each of said compartments, a gas vent connected below the level of the electrolyte in both said exit water seals, and an overflow stand pipe connected with said reservoir and w th said exit water seals, said body portion having in the bottom thereof a passage leading downward and across from the bottom of one compartment to the bottom of the other compartment.

46. An electrolytic cell having opposite porous diaphragm of the class described, supported by said body portion so as to divide the space and the body of electrolyte between the electrodes into two single-polarity, opposite polarity gas compartments, each of said compartn'ients being provided with a water-sealed passage having an upwardly directed opening arranged above the level of the top of the diaphragm and above the level ot' the working surfaces of the electrodes whereby liquid may be automatically discharged into either compartment upon decreasing pressure or lowering level of the electrolyte therein and whereby a dangerous low level of the electrolyte may be indicated by blowing out of the gases through said opening.

at? In an electrolytic apparatus, a pin rality of independent thin metalli tanks each rontaininga separate. |nm-con1munirating bodv oi electrolyte, each tank comprising a thin cast iron frame. a porous diaphragm of the class described supported by said frame, and opposite insulated tlat; walls closing in the cavity within said frame having their respective inner surfaces cxposed for contact with the electrolyte within said tank on opposite sides of said dia phragin and their exterior portions formed with bearing surfaces, said tanks being ar ranged close together with said electrode walls parallel and said bearing surfaces bolted together in electrical contact and mechanical engagement.

43. In an electrolytic apparatus, a plurality of independent thin metallic tanks each cortaining a separate, non-communicating body of electrolyte, each tank comprising a thin cast iron frame, a porous diaphragm of the class described supported by said frame, and opposite insulated flat walls clo In the cavity within said frame liavit", their respective inner surfaces exposed for contact with the electrolyte Within said tank on opposite sides of said diaphra and their exterior portions formed i with bearing surfaces, said tanks being arranged close together with said electrode walls parallel and said bearing surfaces bolted togcther in electrical contact and mechanical engagement each such tank having separate insulating supports secured thereto andhaving suspending means at the top and in line with the center of gravity thereof.

it). In an electrolytic gas generator, a casing comprising two end casing members, a third member comprising a peripherally extending frame or wall insulated from Said end casing members and adapted to form therewith a container for liquid, and means for s curing said members together; and means for keeping the gases produced with in said casing separatifrom one another; said third member having a chamber at its upper end and a tortuous liquid supply passage leading therefrom and discharging into the interior of said casing, a second chamber communicating with the interior of said casing, and a gas ofl'take conduit leading from said last mentioned chamber.

50. .In an electrolytic apparatus, the combination of a plurality of cell units, each including a pair of separate plates formin electrodes, said plates being insulated from each other and in the assembly of the apparatus being arranged side by side, and means between each pair of adjacent cell units for tltttlt'llttbly connectii'ig both structurally and electrically the anode plate of one cell unit to the cathode plate of an adjacent cell unit, whereby each unit may be separately detached from the assembly of units.

Signed at New York city in the county of New York, and State of New York this 31st day of July, A. l). 1917.

lu'DlVARD O. BENJAMIN. 

